Unable to select objects

Hi, im working on a project in inkscape with multiple layers which i have unlocked and locked repeatedly. I now find that certain objects in some layers i cannot select, even when the layer is unlocked. I have confirmed the object is in the layer i have unlocked by toggling layer visibility, and am at a loss as to what the issue could be.
It may be fairly simple as i am quite new to inkscape.
Any help appreciated!

Sometimes, it may happen that the layers dialog doesn't properly update, especially if you lock/unlock layers quickly, due to a bug, which is probably the cause of the issue you see.

To fix, you can either close and restart Inkscape, or rely on the lock icon display in the status bar, which is correct always (to my knowledge). I don't remember if closing/reopening the dialog helped, I think it didn't, but not sure. You might want to try it out.

Additionally, you may want to update your Inkscape version, currently we're at 0.92.2 - your file suggests you're using 0.91.